Show/hide Excel window.
xls_SetVisible([flag])
visible status %t or 1 and %f or 0.
if not specified, used %t.
xls_NewExcel(); xls_AddWorkbook(); xls_SetVisible(%t); sleep(500) xls_SetVisible(%f); sleep(500) xls_SetVisible(%t); sleep(500) xls_SetSave(%t); xls_Close(); xls_Quit();